Scaffold unit construction



1961 K. E. TYLER 2,994,402

SCAFFOLD UNIT CONSTRUCTION Filed July 21, 1958 2 Sheets-Sheet 1 IN l ENTOR 22 2/ Maj wk,

M yw B y $1 Mfg fi 1961 K. E. TYLER 2,994,402

SCAFFOLD UNIT CONSTRUCTION Filed July 21, 1958 2 Sheets-Sheet 2 15 26 26INVENTOR/ ATTORNEYS.

2,994,402 SCAFFGLD UNIT CONSTRUCTION Kenneth E. Tyler, 726 Waveland Ave,Chicago, Ill. Filed July 21, 1958, Ser. No. 749,888 Claims. (Cl.182-152) This invention relates to scaffolding, and more specifically,to the construction of scaffold units which are collapsible andstackable.

Conventional scaffolds are usually heavy and cumbersome structures andare therefore generally unsuitable for use in circumstances requiringscaffolding which is capable of being quickly erected, moved andcollapsed or disassembled as, for example, in the staging of theatricalproductions. Commercially available structures which approximate theweight and mobility requirements are not satisfactory for such purposesbecause they fall considerably short of meeting other essentialrequirements. They either lack the necessary strength and rigidity orthey are incapable of being readily collapsed into compact units forstorage and handling.

Accordingly, one of the main objects of the present invention is toprovide a scaffold unit structure which overcomes the aforementioneddefects and disadvantages of present structures. Another object is toprovide a collapsible scaffold unit of relatively light weight which isextremely sturdy when unfolded and which may be readily collapsed into aflat compact unit for carrying and storage. An additional object is toprovide a collapsible scaffold unit which may be arranged with othersimilar units to form a vertical series or stack, the entire seriesbeing collapsible into fiat condition without first separating theconnected units. A further object is to provide a unit which isextremely stable in both vertical and horizontal directions without theneed for cross bracing between the spaced opposing vertical framesthereof. A still further object is to provide improved locking means inthe form of locking corner gussets for rigidly holding the scaffold inexpanded condition, the locking gussets being readily movable intoreleasing positions when collapsing of the scaffold is desired. In thisconnection, it is a specific object of the present invention to providea removable top or platform which cooperates with the locking gussets toprevent their release when the'parts are assembled.

Other objects will appear from the specification and drawings in which:

FIGURE 1 is a perspective view showing a pair of scaffold units of thepresent invention in nested and expanded condition, the top unit of thecombination being equipped with an attached platform.

FIGURE 2 is a perspective view showing a single expanded unit with theplatform top removed thereform.

FIGURE 3 is a top plan view of a scaffold unit as illustrated in FIGURE2.

FIGURE 4 is a side elevation of an expanded scaffold unit with thegussets thereof in released positions.

FIGURE 5 is a top plan view of the scaffold structure in completelycollapsed condition.

FIGURE 6 is an enlarged sectional view taken along line 66 of FIGURE 1and showing details of the platform attaching means.

Referring to the drawings, FIGURE 2 shows a scaffold unit generallydesignated by the letter A and provided with a pair of side frames 10and '11, and a pair of end frames 12 and 13. The two side frames are ofthe same size and shape, as are the corresponding end frames, and extendalong parallel vertical planes. Similarly, the end frames 12 and 13extend along spaced vertical and parallel planes.

As shown in the drawings, each of the frames is composed ofinterconnected vertical and horizontal tubular ICE.

members. Side frames 10 and 11 are generally rectangular in shape, eachhaving an upper horizontal tube 14, a lower horizontal tube 15, and apair of vertical end tubes or legs 16. These tubular elements are Weldedor otherwise secured together to form the respective frames and may befashioned from steel, aluminum, or any other suitable material.

The end frames 12 and 13 are similarly formed from vertical andhorizontal tubular frame members. Upper frame members 17 and lower framemembers 18 extend horizontally between corresponding pairs of verticalmembers 19 to define end frames of generally rectangular shape. Whilethe end frames as shown consist of several straight pieces of tubingwelded or otherwise secured together at their ends, it will beunderstood that these end frames or selected vertical and horizontalportions thereof may be formed integrally from single sections of tubingbent into the closed rectangular shapes illustrated in the drawings.

In FIGURE 2 it will be noted that the upper members 14 and 17 of theside and end frames all lie along substantially the same horizontalplane adjacent the upper ends of vertical tubes 16 and that the lowermembers 18 of the end frames are disposed intermediate the upper andlower ends of the side frames vertical members. The lower end portionsof the vertical members 15 are reduced in diameter to provide connectingportions 20 which may be received within the sockets of shoes 21 orwithin the sockets provided by the exposed upper ends of the legs orvertical members 16 of another scaffold unit disposed directlytherebelow. Thus, the reduced leg portions 20 and the sockets defined bythe upper ends of vertical legs 16 provide means for securelyinterconnecting successive units of a vertical series When such unitsare stacked. Preferably, shoes 21 are provided with horizontal flangesor bases. 22 which are apertured for securing a scaffold unit, or thelowermost unit of a vertical series to a floor surface.

The vertical members 19 of the end frames are rotatably carried alongthe inner opposing surfaces of legs 16 by hinge tubes 23. The hingetubes are welded or otherwise secured to legs 16 and are disposed inparallel relation to those legs. As shown in the drawings, the hingetubes 23 are somewhat shorter than the vertical distance between theupper and lower horizontal end frame members 17 and 18 so that the endsof the tubes are spaced vertically from those members. Lugs or shoulders19a are welded or otherwise secured to the exposed portions of thevertical members 19 adjacent the ends of the hinge tubes andfrictionally engage those tubes to prevent independent vertical movementof the end frames without, of course, interfering with pivotal movementof such frames.

The scaffold unit of the present invention is rigidly locked in open orexpanded condition by a pair of diagonally disposed gussets 24, each ofthe gussets serving to maintain a right angle relation between the upperhorizontal members of an end and side frame. As shown in the drawings,each gusset has the general shape of a right triangle and, when inlocked or latched position, has its flat upper surface extending alongthe horizontal plane defined by the upper ends of the tubular verticalmembers 16 and 19. A first side portion of each gusset is pivotally andslidably connected to one side of a side frame. to provide a permanentbut rotatable and slidable connection between the parts. A second sideportion (at right angles to the first) extends over the upper horizontalmember of an end frame and is provided with a downwardly turned flange25 which engages the outer surface of members 17 and thereby effectivelyresists forces tending to increase the angle formed by the horizontalframe members con nected by the gusset.

As shown in FIGURES 2, 4 and 6, an inverted U- shaped channel member 26is welded or otherwise secured to the underside of each gusset along thehypotenuse thereof. Another reinforcing member 26a (FIGURES 4 and 6)extends along the underside of each gusset in spaced parallel relationwith depending flange 25. When the gussets are in their horizontallocking positions, the upper horizontal frame members 17 are snuglyreceived between the parallel flanges 25 and members 26a, therebylocking the side and end frames of the scaffold against relative pivotalmovement.

Each of the gussets 24 is provided with a captive screw 27 for securinga top platform 28% in place. Preferably, as illustrated in FIGURE 6,both the reinforcing channel 26 and the gusset plate are provided withaligned apertures through which the captive wing screw or bolt projects.It will be seen that the shank of the screw is reduced in diameter andthat a C-shaped spring 29 extends about the screws reduced portion tohold it in place even when it is not threaded into the recess of aplatform fitting.

The top 28 may be formed from plywood or any other suitable material andis recessed along its under-surface to receive threaded fittings 30.These connecting fittings are secured to the under surface of theplatform by screws 31 or by any other suitable means, and, as shown inFIGURE 6, are flush with the lower surface of that platform.

It is believed apparent that when the captive screws of the gussets aretightened within the threaded fittings of the platform, the platformsunder surface is drawn into tight contact with the flat upper surfacesof the gussets. Since the depending flanges 25 of the gussets willrelease the transverse frame members 17, only when the gussets arepivoted upwardly about their rotatable connections to longitudinal framemembers 14, and since the two cap tive screws hold thediagonally-disposed gussets in tight surface contact with the platform,the platform effectively cooperates with the gussets to hold thesegussets in locking positions.

Preferably, the platform 28 is provided with a metal edging 32 toreinforce and protect the edges of the plywood panel. In FIGURES l and 6it will be noted that the edges of the platform are substantially flushwith the sides and ends of the scaffold and that there are no tubularframe members which project outwardly beyond those edges. Hence, aplurality of scaffold units may be placed side-by-side with the platformtops of the respective units providing a substantially continuoussupport surface.

In the structure illustrated in the drawings, I have provided certain ofthe legs 16 with horizontally and inwardly projecting pins 33 adapted tobe engaged by hooks 34 of of the hinge tubes 23 and their relation tomembers 19,

and the substantial surface contact between the corner gussets and thehorizontal frame members 14 and 17.

Thus, longitudinal distorting forces applied to the upper part of theunit will be effectively resisted by the gussets 24 and by the elongatedhinge connection of those gussets to the longitudinal frame members 14.Similarly, should lateral forces be directed against the upper part ofthe unit, the tubes which hold the vertical members 19 of the end framesalong the legs 16 of the side frames will prevent such forces fromlaterally distorting the structure.

In this connection, lugs 19a play an important part in preventingvertical displacement of the end frames with reference to the sideframes, thereby insuring structural rigidity. As a result, even where anumber of such units are stacked one upon the other, the vertical seriesprovides extremely firm and unyielding support and will not sway ineither longitudinal or lateral directions.

To collapse or fold the scaffold unit, the platform top 28 is firstremoved and the corner gussets are then pivoted about longitudinal framemembers 14 into the vertical released position illustrated in FIGURE 4.A worker standing at one corner of the scaffold may then urge an endframe into parallel relation with the adjacent side frame to which it ishingedly connected, thereby folding the scaffold into the collapsedcondition shown in FIGURE 5. In its flat collapsed state the compactscaffold may be easily moved from place to place or may be stored in arelatively small amount of space. It will be noted that even when thescaffold unit is collapsed there are no members which project laterallybeyond the outermost vertical planes of the side frames.

Where several scaffold units are arranged in a vertical stack it is notnecessary to separate the units before fully collapsing them. Forexample, the two unit arrangement shown in FIGURE 1 may be collapsed byfirst removing the platform top 28, then lifting and releasing thecorner gussets of both units, and finally folding both unitssimultaneously while they are still in stacked relation. Suchsimultaneous folding (or unfolding) of two or more nested units isparticularly important in theatrical presentations where the timealloted for the changing of scenery and sets may be extremely limited.

Since the lower members 18 of the end frames are disposed substantiallyintermediate the upper and lower ends of legs 16, it is apparent thatwhen several units are stacked the members 18 will be spacedsubstantially equidistant from the end frame members 17, disposeddirectly therebelow and therea-bove, (FIGURE 1). As a result, theparallel and substantially uniformly spaced frame members .17 and 18provide an effective ladder for climbing upwardly and downwardly alongthe stacked units.

Normally, the gussets 24 are released by simply pivoting them upwardlyand laterally about horizontal tubular frame members 14. However, whensuch units are arranged in a vertical series, it will be noted (FIG-URE 1) that the lower horizontal member 15 of the scaffold unit disposeddirectly thereabove will prevent the gussets from being swung about 270arcs into their depending released positions. Despite this restrictionimposed by the lower horizontal members, the gussets may still bequickly and easily released by simply lifting them until flanges 25 aredisposed above the upper members 17 of the end frames and then slidingthe gussets longitudinally along upper side members 14 until the gussetscan be dropped downwardly into their vertical positions withoutinterference from members 17.

While I have disclosed an embodiment of the present invention inconsiderable detail for purposes of illustration, it will be understoodby those skilled in the art that many of these details may be variedconsiderably without departing from the spirit and scope of theinvention.

I claim:

1. A collapsible scaffold having parallel side and end frameshingedlyconnected at the corners thereof, said side and end frameshaving horizontal upper frame members all lying along substantially thesame horizontal plane, a pair of diagonally disposed gussets each beinghingedly connected along one edge portion thereof to a horizontal memberof one of said frames for pivotal movement about its respective pivotaxis between a substantially horizontal raised position and asubstantially vertical lowered position and having a secondedge portionadapted to rest upon and to interlock with a horizontal member of anadjacent frame when said gusset is in raised position, and a removableplatform top resting upon and detachably secured to said gussets whenthe same are in raised positions, said top and gussets cooperating toprevent pivotal movement of the gussets and to prevent collapsing ofsaid scaffold when said top is in place and secured to said gussets.

2. A collapsible scaffold unit comprising a pair of vertical andparallel side frames, a pair of vertical and parallel end framesextending between said side frames at the ends thereof and beinghingedly connected to said side frames for movement into positionsparallel with the side frames when the scaffold is collapsed and intopositions disposed at right angles to the side frames when said scaffoldis fully expanded, said side and end frames being provided withhorizontal tubular members disposed at substantially the same elevation,and a pair of diagonal- 1y disposed locking gussets each extendingbetween horizontal tubular members of a side and end frame adjacent thehinged connection thereof, each gusset being rotatably mounted upon oneof the horizontal tubular members of said respective side and end framesfor movement between a lowered vertical position beneath the horizontalmember upon which the same is mounted to permit movement of the side andend frames into substantially parallel relation as the scaffold unit iscollapsed and a raised horizontal position interlocking with thehorizontal tubular member of the other of said frames for locking saidscaffold in expanded condition, each of said gussets being provided withconnecting means adapted for securing a platform upon the top of saidscaffold unit.

3. In a collapsible scaffold structure having hingedly connected sideand end frames each formed from horizontal and vertical tubular members,a corner gusset for releasably locking a side and end frame againstrelative movement, said gusset having one side portion pivotally securedto a horizontal member of one of said frames for pivotal movement ofsaid gusset between a substantially horizontal raised position and asubstantially vertical lowered position, said gusset having a secondside portion adapted to rest upon and to lock with the horizontal memberof an adjacent frame when said gusset is raised, whereby, said frames ofsaid scaffold are locked together by said gusset when the same is raisedand are released for relative pivotal movement when said gusset islowered, said gusset when lowered being suspended beneath the horizontalmember to which the same is pivotally secured to permit movement of saidside and end frames into substantially parallel relation when saidscalfold structure is collapsed, said scaffold also being provided witha removable platform top, and means for connecting said gusset to saidtop in surface engagement therewith when said gusset is raised toprevent movement of said top and to prevent pivotal movement of saidgusset.

4. A collapsible scaffold unit comprising a pair of vertical andparallel side frames, a pair of vertical and parallel end framesextending between said side frames at the ends thereof and beinghingedly connected to said side frames for movement into positionssubstantially parallel with the side frames when said scaffold iscollapsed and into positions disposed substantially at right angles tosaid side frames when the scaffold is fully expanded, said side and endframes being provided with horizontal members disposed at substantiallythe same elevation, a pair of locking gussets each extending betweenhorizontal members of a side and end frame adjacent the hingedconnection thereof, each gusset being rotatably mounted upon one of thehorizontal members of said respective side and end frames for movementbetween a lowered depending position to permit movement of the side andend frames into substantially parallel rel-ation as the scaffold unit iscollapsed and a raised substantially horizontal position interlockingwith the horizontal member of the other of said frames for locking saidscaffold in expanded condition, the respective gussets being swingableabout respectively different pivot axes, each of said gussets beingprovided with connecting means for securing a platform upon the top ofsaid scaffold unit.

5. The structure of claim 4 in which said locking gussets are diagonallydisposed with reference to said scaffold unit.

References Cited in the file of this patent UNITED STATES PATENTS1,466,757 Riemer Sept. 4, 1923 2,599,670 Thomas June 10, 1952 2,720,430Meng et al. Oct. 11, 1955 2,820,256 Dahl Jan. 21, 1958 2,872,251 CrosbyFeb. 3, 1959

